1. Field of the Invention
This invention relates to electric circuit modules.
More particularly the invention relates to electric circuit modules of the kind having a generally shallow box-like form and adapted to be mounted, e.g. by sliding action, in a rack, the module incorporating a path for the conduction of heat away from components of the module. A module of such a kind allows a number of modules to be accommodated compactly in a rack in parallel spaced relationship, without overheating problems, thus rendering the rack and its several modules suitable for locations where space is limited, for example, in vehicles.
2. Description of Related Art
A previously proposed, although hitherto undisclosed, module of the aforesaid kind comprises: a central heat conductive plate; two substrates adapted to carry electric circuit components and secured to the central plate one on each major surface thereof; two cover plates respectively serving as covers for the two substrates and electrical components carried thereby; and two elongate expansion devices extending lengthwise along lateral surface portions at opposite sides of one major surface of the central plate. In use of the module the said opposite lateral surface portions and their respective expansion devices are received within respective channels in opposed walls of a rack. Operation of the expansion devices by reaction with onc of the side walls of the relevant channel and contact with the lateral surface portion drives correspondingly disposed lateral surface portions at opposite sides of the other major surface of the central plate into intimate contact with the opposite wall of the channel. Heat from electrical components carried by the substrates is then transferred to the central plate and, from thence, to the rack in which the module is held by heat conduction along well defined heat paths in the module. Normally there is attached to a side of the module extending between the lateral surface portions which contact the rack one part of a two-part electrical connector the other part of which is on the rack. The connection when made serves in the transmission of power and data signals to and from the electrical components of the module. One such previously proposed module is described in greater detail hereinafter.